There are regular specialty batteries, and then there are Energizer specialty batteries. Choose the durable Energizer 386 silver oxide button cell for reliable performance. This battery provides long-lasting energy for all your button cell devices, from household electronics like keyless entry systems to e-book readers, toys, calculators, and watches, as well as heart rate and blood sugar monitors. The mercury-free button cells are also ready to use after storage of up to 5 years. Choose Energizer specialty batteries for dependable energy you can count on.